Pulverized materials such as flour and cement and the like are transported in enclosed tanks, either in the form of railroad tank cars or tank trucks, and transferring the material into and out of the tanks is accomplished by a closed pressurized air transfer system. Such finely divided materials must be aerated prior to being pneumatically conveyed by a closed pressurized air system. The tank is, of course, sealed and pressurized to force the material out through a number of one or more discharge openings provided in the bottom of the tank.